How long to heat water

[mkotubs]

I just refilled my tub this weekend for the first time any was wondering about what is the normal amount of time it takes to heat the tub?

I know this depends on the number of gals, size of heater, and outside temp.  

I have HS Vista, so 500 Gals, and 4000 Watt heater.  The water temp was 55 after filling, and it took over 9 hours to heat.  Turned on spa at 3:00pm, checked the water at midnight, still heating.  Woke up at 5:30am, tub was ready.

Is 9 plus hours normal?

[Spatech_tuo]

I just refilled my tub this weekend for the first time any was wondering about what is the normal amount of time it takes to heat the tub?

I know this depends on the number of gals, size of heater, and outside temp.  

I have HS Vista, so 500 Gals, and 4000 Watt heater.  The water temp was 55 after filling, and it took over 9 hours to heat.  Turned on spa at 3:00pm, checked the water at midnight, still heating.  Woke up at 5:30am, tub was ready.

Is 9 plus hours normal?

I've always told people to assume about 5-8º per hour on a 220v spa but there are many variables with tub size being a key one and at 500 gallons yours is a big one.  Yours was 5º/hr which isn't abnormal with that volume.

[nlittle]

I've always told people to assume about 5-8º per hour on a 220v spa but there are many variables with tub size being a key one and at 500 gallons yours is a big one.  Yours was 5º/hr which isn't abnormal with that volume.

Yikes!
I will be setting up a Prodigy tomorrow on 115v.  325 gallons....  

[Tatooed_Lady]

I want to say that it takes roughly 10-12 hours to warm our tub up from tap to the 101 range...500 gallon Grandee.

[pg_rider]

My 485 gallon Optima went from 61 deg to 102 deg in less than eight hours (connected the electricity at 10am and went to work, it was fully heated when I got home around 5:30).  For all I know it was hot much earlier than that, but I would say conservatively it took seven hours to go up 41 degrees... so call it 6 deg/hr.

[Chad]

336 gallon tub. 7 degress an hour average.

[Brookenstein]

My Envoy averages only 4 degrees an hour and that is with the SoCal climate.  My water last week entered at 64 degrees and took until after bedtime to be 100.  Filled around 11am.

[Chas]

110 volt tubs will only do around 2-3 degrees per hour.

 8-)

[TN__HOT_TUB]

I think mine heats at about 5 degrees per hour (quicker in the summer).

During the cold months I try to heat the water during the warmest part of the day.  I might even hold off a couple days if the weatherman says a warm front is coming my way.

This time of year around here (East TN) the air cools down pretty quickly around dusk (5PM ish).  I'm probably going to change my water this weekend and will try my best to begin heating by 11AM.

[mkotubs]

Ok, so it seems the average is 7 - 8 degrees per hour for a 220 amp tub.  So no need to place a service call

thanks for the replies.

[bwbski22]

what i did, was when i just built my new house i had the plumber install a hot water line outside by my tub so i can fill it with a mix of hot water and cold water, using two hoses at once.  that way the tub will fill twice as fast, so i can start the tub up twice as fast, and the starting heating temp will be a lot higher to speed up the heating process.  Im thinking my tub will be ready to soak in, in less then 3 hours.   its a brand new j470 waiting to get filled this week.  ill let you guys know how long it takes.

[Tatooed_Lady]

bwb, unless I'm mistaken, even if you had 8 hoses, the water can only come through the main line to your house at so many GPM....to use a hot and a cold might warm the water faster (depending how big your water heater is), but it doesn't seem like it'd really make too much difference in the end....and if you've got a 50 gallon water heater (I think that's what we've got here?), and a 500 gallon tub.....you're still looking at 450 gallons of COLD water going in.
Of course, you've probably got some other on-demand water heating system that'll make my post moot, but yanno I have to throw this out, anyhow.

[Brewman]

 If indeed you did install a standard sized tank style water heater, which in these parts is 40 gallons, you won't get much benefit at all- the tank will quickly drain, and won't be able to produce hot water, since it will be constantly draining thruout the fill process.

Honestly, that approach is way overkill, IMHO.  Just fill the spa with cold water and let the spa heat it.  So you loose the use of the spa for maybe 12 hours, and only a few times per year.  

If you are using one of those tankless water heaters, you might get some benefit in faster heated water.  But I wouldn't spend much time or money if the only benefit you want is potentially faster heated or filled spa water.

And I'm not sure at what rate those on demand heaters can supply hot water.  I'd think if you were pulling too much water thru you'd get less heat into it.


  

[bwbski22]

well for one loosing a day of use of the tub at my vacation home that i only use on weekends is a big deal to me.  when skiing all day and wanting to use the tub afterwards, doesnt leave much time for traditional drain and fill up in vermont.  and with contious hot water, it will make a big difference in the heat time.